In this heat metal spell you need to chose a manufactured metal object which you can able to see within a range such as one metal weapon or one suit of heavy or medium metal armor. Perhaps you cause the object to glow into red-hot. Any of the creature which is physically contacted by an object would take 2d8 fire damage whenever you cast this d&d 5e heat spell.
Until the end of this spell, you can able to use a bonus action as easily as you can on each of your subsequent turns to cause this damage once again.
Suppose the creature which is holding or wearing the object and even takes the damage from this then that creature must be succeed on a constitution saving throw or else it should drop the object if it can. But if the creature does not drop the object then it has disadvantage on the attack rolls and also ability checks until unless start of your next turn.
You can also check out: aura of purity 5e spell
At Higher Levels:
Whenever you cast this heat metal spell by using the spell slot of 3rd level or more than the 3rd level, the damage would increase by 1d8 for each slot above the 2nd level.
Attributes Of D&D Heat Metal Spell
|Casting Time||1 action|
|Components||V S M|
|Duration||Up to 1 minute|
|Higher Spell Slot Desc||When you cast this spell using a spell slot of 3rd level or higher, the damage increases by 1d8 for each slot above 2nd.|
|Higher Spell Slot Dice||1|
|Higher Spell Slot Die||d8|
|Material||A piece of iron and a flame|
|Target||A manufactured metal object that you can see within range|